Hem Flange Adhesive Extrusion Prevention
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Solution Overview
Problem
Current adhesive technologies used in seam bonding for flanged folds are prone to being pressed out during the flanging process, resulting in aesthetically undesirable residue and requiring additional cleaning, and are not suitable for spray applications.
Innovation Solution
A method involving a one-component heat-curing epoxy resin composition applied to the inner or outer panel, crimped and pressed to ensure the adhesive remains within the fold, with a specific formulation including epoxy resin, latent hardener, and crystalline polyester polyol to prevent adhesive extrusion and enhance bonding strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional adhesives are used in hem seam bonding, then the adhesive provides basic bonding function, but the adhesive is squeezed out of the hem during the hem seam process
Solution Approach 1:
The patent changes the viscosity parameter of the adhesive by selecting specific polymer types (polyester, polyurethane, acrylic) with controlled molecular weights and ratios. This parameter adjustment ensures the adhesive maintains appropriate consistency to prevent extrusion during hemming while still providing reliable bonding.
Solution Approach 2:
The patent uses composite adhesive formulations combining multiple polymer components (polyester segments, polyurethane segments, acrylic segments) with specific ratios. This composite approach creates an adhesive that leverages the properties of each component to achieve both non-extrusion and strong bonding performance.
2Ease of manufacture
If conventional adhesives are used, then basic bonding is achieved, but adhesive residues outside the flange require additional cleaning process
Solution Approach 1:
By adjusting the viscosity and consistency parameters of the adhesive through careful polymer selection and ratio control, the adhesive is formulated to remain contained within the flange during hemming, eliminating the need for subsequent cleaning operations and saving time.
3Adaptability or versatility
If common adhesives are used, then traditional bonding is achieved, but the adhesive is not suitable for spray applications
Solution Approach 1:
The patent adjusts the viscosity and flow characteristics parameters of the adhesive by selecting specific polymer combinations, making the adhesive suitable for spray application methods while maintaining bonding performance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The method effectively prevents adhesive extrusion during flanging, allows for aesthetically clean seams, and supports strong bonding suitable for spray applications, with improved mechanical properties such as tensile strength and impact peel resistance.
Implementation Method 1
a one-component heat-curing epoxy resin composition
Implementation Method 2
epoxy resin composition... latent hardener for epoxy resins
Data Source
AI summary
The present invention relates to a hem flange bonding method. According to this method, a single-component heat-curing epoxy resin composition comprising 20 -60 wt.% of at least one epoxy resin A, a latent curing agent for epoxy resin B, 10-40 wt.% of a toughness enhancer D and 4-12 wt.% of a crystalline polyester polyol PP that is solid at room temperature are used, allowing compositions that are suitable for spray applications and that are not forced out of the hem flange during hemming.